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<h1>Tennis Equipment</h1>

<p>As the popularity of tennis raised tennis players required more consistency
in their tennis equipment. As the materials became more readily
available for tennis innovators, more and more technological
advancements were made to every aspect of the sport.</p>

<img src="http://www.orchardtennis.com/images/tennis_equipment/tennis_equipment_250x251.jpg" alt="" />

<h3>Racquet</h3>
<p>By far the most drastic change in technology was in the tennis
racquet. Every aspect of the tennis racquet from the weight of the
racquet to the shape of the racquet changed to better suit modern tennis
players. The parts of a tennis racquet are the head, rim, face,
neck,butt/butt cap, and handle.</p>

<p><b>Specifications:</b> Modern tennis racquets vary in length,
weight, and head size. 21" to 26" is normally a junior's length, while
27" or 27.5" are for stronger and taller adult players. Weights of a
racquet also vary between 8 ounces unstrung and 12.5 ounces unstrung.
Racquets originally flared outward at the bottom of the handle to
prevent slipping. The rounded bottom was called a bark bottom after its
inventor Matthew Barker. But by 1947 this style became superfluous. Head
size also plays a role in a racquet's qualities. A larger head size
generally means more power, and a larger "sweet spot" that is more
forgiving on off-center hits. A smaller head size offers more precise
control. Current racquet head sizes vary between 88 sq. inches and 137
sq. inches.</p>

<p>Stringing (material, pattern, tension) is an important factor in
the performance of a tennis racquet. A few elite players use natural
gut, but the vast majority of strings are a nylon or polyester
synthetic. Some (American champion Pete Sampras is a prominent example)
consider the natural string to be more responsive, providing a better
"feel", but synthetic is favored for its much superior durability,
consistency, as well as much lower cost. String pattern (the
vertical/horizontal grid) is a function of the racquet head size and
design. A tighter pattern is considered to deliver more precise control;
a more "open" pattern to offer greater potential for power and spin.
Modern racquets are marked with a recommended string tension range. The
basic rule is that a lower tension creates more power (from a
"trampoline" effect) and a higher string tension creates more control
(the less 'trampoline effect' the more predictable the power and angle
of the departure from the string bed.)</p>


<h3>Ball</h3>
<p>A tennis ball is a ball designed for the sport of tennis,
approximately 6.7 cm (2.7 in.) in diameter and is usually bright
yellow-green, but in recreational play can be virtually any colour.
Tennis balls are covered in a fibrous fluffy felt which modifies their
aerodynamic properties.</p>

<p>Tennis balls must conform to certain criteria for size, weight,
deformation, and bounce criteria to be approved for regulation play. The
International Tennis Federation (ITF) defines the official diameter as
65.41-68.58 mm (2.575-2.700 inches). Balls must weigh between 56.0g and
59.4g (1.975-2.095 ounces). Yellow and white are the only colours
approved by the United States Tennis Association (USTA) and ITF, and
most balls produced are fluorescent yellow (known as "optic yellow") the
colour first being introduced in 1972 following research demonstrating
they were more visible on television. Tennis balls are filled with air
and are surfaced by a uniform felt- covered rubber compound. The felt
traps the air flow boundary layer which reduces aerodynamic drag and
gives the ball better flight properties.</p>
<p>Often the balls will have a number on them in addition to the
brand name. This helps distinguish one set of balls from another of the
same brand on an adjacent court</p>

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	Why does balls are in many cases numbered?
		<gale:answer correct="false">For round-robin rotation	</gale:answer>
		<gale:answer correct="true">Distinguish one set of balls from other set on an adjacent court	</gale:answer>
		<gale:answer correct="false">For statistics</gale:answer>
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	A higher string tension creates more control
		<gale:answer correct="true">true	</gale:answer>
		<gale:answer correct="false">false</gale:answer>
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<h2>External references</h2>
<ul>
	<li><a
		href="http://www.tennisexpress.com/category.cfm/tennis/tennis-racquets">Tennis
	Racquet Info</a></li>
	<li><a href="http://www.madehow.com/Volume-3/Tennis-Racket.html">Rackets,
	Technology</a></li>
</ul>

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